import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class LC_15 {
    public List<List<Integer>> threeSum(int[] nums) {
        List<List<Integer>> result = new ArrayList<>();
        Arrays.sort(nums);
        for(int i = 0; i < nums.length; i++){
            if(nums[i] > 0)return result;
            if(i > 0 && nums[i] == nums[i-1]){
                continue;
            }
            int right = nums.length - 1;
            int left = i+1;
            while(right > left){
                if(nums[i] + nums[left] + nums[right] > 0){
                    right--;
                }else if(nums[i] + nums[left] + nums[right] < 0){
                    left++;
                }else{
                    result.add(Arrays.asList(nums[i], nums[left], nums[right]));
                    while(right > left && nums[right] == nums[right-1]){right--;}
                    while(right > left && nums[left] == nums[left+1]){left++;}
                    right--;
                    left++;
                }
            }

        }
        return result;
    }
}
